Earlier this year there was a sudden rash of concerned pronouncements about a coming population decline. Fears of the much-dreaded ‘birth dearth’ were being revived: soon, very soon, world population would begin an inexorable decline with catastrophic implications for the global economy and the future of humankind.

Among the birth dearth alarmists, Jonathan V. Last is in first place. The author of What to Expect When No One is Expecting, he vigorously asserts that world population will be declining within 50 years and that for the past forty years people everywhere have been having “too few babies.” His concern about population applies with special urgency to the U.S. He stresses that “if America wants to continue to lead the world, we need to have more babies.”

To paraphrase Mark Twain’s famous retort about rumors of his death, “Reports of an impending population decline have been greatly exaggerated.” As it turns out, fertility rates are not falling as fast as previously projected and neither U.S. nor world population show any signs of declining any time soon. To the contrary, world population projects are on the rise again. According to the UN’s latest forecast, issued just a few weeks ago, it appears that world population will reach 7.2 billion next month, and is on course to exceed 9.6 billion by 2050 and 10.9 billion by the end of the century. And as for the U.S., the UN projects that America’s population, currently 320 million, will rise to 400 million by mid-century and 462 million by 2100.

It’s easy to dismiss concerns about a global or U.S. birth dearth. All you have to do is examine fertility rates and review the latest demographic projections. We’re not in any danger of shuffling off our demographic coils, not even in the developed world. While the population of some developed nations, most notably Russia and Japan, are declining, the UN’s latest report indicates that the population of the entire developed world is expected to increase from 1.25 billion today to 1.3 billion in 2050. Fertility rates in many developed countries are on the rise again.

The real problem with Jonathan Last and the ‘birth dearth’ alarmists is not their faulty demographics; it’s that they cannot comprehend what human numbers are doing to the planet. They perpetuate the idea that humanity poses no challenge to the planet and that planetary limits pose no challenge to humanity. In promoting his book, Last blithely dismisses the idea of resource limitations. He asserts that since the 1970s “commodity prices have continued to fall.” Really? Commodity prices in the past decade have soared. The prices of basic food commodities have essentially doubled. The prices of most metals and minerals have tripled, and the price of oil has quadrupled.

Last also insists that Americans, despite our increasing numbers, are doing less environmental harm than we did fifty years ago. Well our air and our rivers may be cleaner today, but America’s deleterious impact on the global environment continues to grow. Our greenhouse gas emissions have soared over the past half century and our over-sized consumption of material goods has contributed to deforestation, the acidification of the oceans, and the exhaustion of the world’s limited inheritance of natural resources.

Last and many others also argue that the planet is not overcrowded, there’s plenty of land, as if the concern about population is one of physical overcrowding. But it’s never been a question of how many people the world can contain; it’s how many people the world can sustain… at what standard of living…and for how long. And the evidence is strong, if not overwhelming, that we are already exceeding the Earth’s regenerative capacity. In many areas of the world, lakes and rivers are shrinking and water tables are falling precipitously. Around the world, arable land is in short supply and topsoil is being eroded at a worrisome rate. Deserts are expanding and forests are contracting.

We already have close to 1 billion hungry people in the world and that number shows no sign of shrinking. Given the challenges posted by climate change and the rising costs of fuel and fertilizer, no one knows whether farmers will be able to produce enough food at affordable prices to feed the projected 9.6 billion people just 37 years from now.

We are quickly exhausting all the easily accessible metals and minerals that the Earth has to offer. That’s why commodity prices have soared over the past decade. A generation or two hence when food and resources constraints are dramatically apparent, our children will look back and ask, “What were they thinking?” The answer, of course, is that we were listening to people like Jonathan Last who insisted that we needed still more people, not fewer.

Those who are insisting that we desperately need more babies have an obligation to explain how we are going to feed, cloth, and house them…and their children. Last and others insist that “innovation” will solve all of our problems, and that more babies will yield more innovation. Alas, humanity cannot live on innovation alone.